Evaluate the following expression when $c = 2$ and $d = 5$. $3$ $c$ $ + 8$ $d$ $ - 9$
Explanation: Substitute $2$ for ${c}$ and $5$ for ${d}$ $ = 3{(2)} + 8{(5)} - 9 $ $ = 6 + 40 - 9 $ $ = 37$